1. Field of the Invention
The present invention relates to a stage apparatus and a vision measuring apparatus, in particular to a stage apparatus and the like used, for example, for a vision measuring apparatus, which measures contour, dimensions etc. of an object to be measured based on image data obtained by imaging the object, and illuminates the object with contour illumination.
2. Description of Related Art
Conventionally, such a vision measuring apparatus that measures contour and dimensions of an object to be measured based on images obtained by imaging the object has been known (refer to, for example, Document; JP2001-41711A).
Such a vision measuring apparatus includes, for example, as shown in FIG. 8, a stage glass 210 as a stage for setting an object W to be measured thereon, an imaging device 514 for imaging the object W, an illuminator 700 that performs contour illumination against the object W through the stage glass 210, a movement mechanism 600 for moving the imaging device 514 and the illuminator 700 in accordance with the portion to be measured of the object W and an analyzing unit (not shown) for analyzing and processing images taken by the imaging device 514.
The stage glass 210 has a stage surface 211 on which an object W to be measured is set, and the stage surface 211 is formed into a flat plane free from unevenness, waviness or the like.
A movement mechanism 600 is equipped with a Y-movement mechanism 610 that moves the imaging device 514 and the illuminator 700 along the Y-direction, which is one of the parallel direction to the stage surface 211 of the stage glass 210, and an X-movement mechanism 620 that moves the imaging device 514 and the illuminator 700 along the X-direction, which is parallel to the stage surface 211 and perpendicular to the Y-direction.
The Y-movement mechanism 610 is equipped with Y-axis guides 611, 611, which are disposed parallel to each other within a flat plane parallel to the stage surface 211 interposing the stage glass 210, and Y-sliders 612, 612 arranged in slidable manner on each of the Y-axis guides 611, 611.
The X-movement mechanism 620 is equipped with a first X-axis guide 621 of which both legs are fixedly attached to the Y-sliders 612, 612, and are disposed parallel to the stage glass 210 facing the stage surface 211 side of the stage glass 210, a second X-axis guide 622 of which both legs are fixedly attached to the Y-sliders 612, 612 and are disposed parallel to the stage glass 210 facing at the opposite side of the stage surface 211 of the stage glass 210, a first X-slider 623 mounted in slidable manner on the first X-axis guide 621 and a second X-slider 624 mounted in slidable manner on the second X-axis guide 622.
The imaging device 514 is attached to the first X-slider 623, and the illuminator 700 is attached to the second X-slider 624.
In configuration as described above, a display-panel, for example, is set on the stage surface 211 of the stage glass 210 as an object W to be measured. The imaging device 514 and the illuminator 700 are moved by the Y-movement mechanism 610 and the X-movement mechanism 620 in accordance with the portion to be measured. While performing contour illumination by the illuminator 700, images of the object W are taken by the imaging device 514. Then, an analyzing unit (not shown) analyzes the images based on the image data, and the contour and dimensions of the object W are measured.
Recently, the size of the object W is getting larger. For example, a display panel as an object W has 2500 mm×2500 mm in size. The size of the stage glass 210 for setting such a large object W also has to be made larger.
However, if the stage glass 210 is simply made larger, flexure is generated due to its own weight. For example, in a glass of 25 mm in thickness and 2500 mm×2500 mm in size, the flexure due to its own weight reaches to an extent of 0.8 mm to 1.8 mm. When the stage glass 210 deflects as described above, the object W also deflects; thus, there resides such a problem that the measurement is hardly carried out precisely.
Here, in order to adjust such flexure of the stage glass 210, it is conceivable to support the lower surface of the stage glass 210 using, for example, jacks. However, in this case, the jacks block movement of the illuminator 700 bringing about areas out of reach and thus areas with no illumination are generated.
Therefore, an arrangement for measuring a large object W using the contour illumination has been strongly demanded.